Local solar firm will help test pilot energy storage system

Two solar companies working in Hawaii have been selected to test a new energy storage technology that could help connect more rooftop photovoltaic systems to the electric grid.

Enphase Energy Inc. said Tuesday that locally owned Hawaii Energy Connection and Lehi, Utah-based Vivint Solar are two of the three companies in the U.S. that will run a pilot program for Enphase’s battery and energy management system.

The Enphase pilot program could be helpful as the utility works to get more rooftop solar systems connected to the grid, said Hawaiian Electric Co.

"We continue working with Enphase, one of the leading suppliers of inverters used in Hawaii, on technical changes and upgrades to allow us to integrate more rooftop solar on our grids, particularly on heavily loaded circuits," said Peter Rosegg, HECO spokes­man. "If it performs as Enphase hopes, it could help with grid stability while letting more customers enjoy the benefits of rooftop solar."

Petaluma, Calif.-based Enphase Energy uses a 40-pound lithium iron phosphate battery to smooth out the fluctuating energy that rooftop solar systems send into the grid. The 6-inch-wide battery provides 1.2 kilowatt-hours of energy storage, or about enough to power 12 lights for one hour.

The Enphase battery will be available in the second half of 2015.

"What this battery does, coupled with the photovoltaic systems, is it allows a proportion of its solar generation to be stored and levels the production during the day and shifts that power later into the evening to when it is needed, when people come home," said Chris DeBone, managing partner at Hawaii Energy Connection.

The battery is not meant to allow homeowners to get off the grid, but to smooth out power being sent to or pulled from the grid.

"It allows you to store some of that solar energy and put it into the grid at more optimum times of the day," DeBone said.